Echocardiographic Evaluation of Myocardial Changes Observed After Closure of Patent Ductus Arteriosus in Dogs

BACKGROUND Closure of PDA can be associated with echocardiographic changes including deterioration of LV systolic function. Although PDA is commonly encountered in dogs, few comprehensive reports of echocardiographic changes in dogs with PDA closure are available. OBJECTIVES To evaluate the short-term echocardiographic changes observed after PDA closure in dogs using strain analysis. ANIMALS Seventeen client-owned dogs with left-to-right PDA. METHODS Echocardiographic evaluations, including standard echocardiography and two-dimensional tissue tracking (2DTT), were performed before and within 3 days of PDA closure. RESULTS Preclosure examination showed LV and left atrial dilatation indicating volume overload as a result of PDA. Closure of PDA resulted in significant reduction of LVIDd (<.0001) and LA/Ao (0.01) without change in LVIDs, suggestive of decreased preload. Postclosure LV systolic dysfunction was observed with significant decreased in FS (<.0001) and strain values (P = .0039 for radial strains, P = .0005 for circumferential strains). Additionally, significant LV dyssynchrony (P = .0162) was observed after closure of PDA. CONCLUSIONS AND CLINICAL IMPORTANCE Closure of PDA resulted in decreased preload as a result of alleviation of LV volume overload, which in turn caused transient deterioration of LV systolic function. Additionally, this study demonstrated that strain analysis is load dependent. Therefore, care should be taken when interpreting strain measurements as an indicator of LV systolic function.